26-30 October 2015
Asia/Tokyo timezone
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Contribution Oral presentation

Gamma-ray Astrophysics

MAGIC detection of very-high-energy gamma-ray emission from the z = 0.94 blazar PKS 1441+25



Primary authors


  • Dr. Marina MANGANARO (Inst. de Astrofı́sica de Canarias, E-38200 La Laguna, Tenerife, Spain; Universidad de La Laguna, Dpto. Astrofı́sica, E-38206 La Laguna, Tenerife, Spain)
  • Dr. Fabrizio TAVECCHIO (INAF National Institute for Astrophysics, I-00136 Rome, Italy)
  • Dr. Josefa BECERRA GONZÁLEZ (NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA)

Abstract content

Very-high-energy (VHE, E > 100 GeV) gamma-ray emission from the very distant flat spectrum radio quasar PKS 1441+25 (z = 0.940) was detected in April 2015 with the MAGIC telescopes. Aside from the gravitationally lensed VHE blazar QSO B0218+357 (z = 0.944), also detected by MAGIC, PKS 1441+25 is the most distant VHE blazar detected to date. The VHE detection occurred in April 2015 during enhanced activity of the source at high energy (HE, 0.1 GeV < E < 100 GeV), as measured by the Large Area Telescope on board Fermi. The multi-wavelength light curve shows two distinct flux states occurring during this flare. The broadband spectral energy distribution can be explained by an external Compton model. For the first time, the VHE gamma-ray spectrum was used to indirectly probe the extragalactic background light at redshifts out to z ~ 0.94.